Off the highest of my head …
ExtraNonce: In addition to the Nonce area, There’s additionally an extranonce conference – part of the unlocking script within the enter of the coinbase transaction is used as an additional nonce by miners.
Timestamp: The miner can fluctuate the timestamp. It solely must be correct inside about 2 hours. It does not must be higher than the timestamp of the earlier block.
Model: Miners can fluctuate part of the model quantity. There’s a methodology often known as ASICboost which helps miners who’re utilizing ASICs for mining.
Coinbase output: The miner can fluctuate the coinbase output. Maybe choosing a distinct receiving tackle or various the kind of script.
Transaction order: The miner can fluctuate the order of transactions (apart from for transactions that spend outputs of prior transactions in similar block).
Transactions: The miner could make an arbitrary choose of transactions from their mempool or create their very own new arbitrary legitimate transactions to incorporate. If inventing their very own transactions they’ll fluctuate the charge from zero to most and might fluctuate the transaction kind from legacy to newest. They will additionally fluctuate the enter quantities from close to zero to complete UTXO. The transactions have to be legitimate however that also permits an unlimited vary of variations, assuming the miner owns some bitcoin to start out with.
Desk 2. The construction of a coinbase transaction enter
Measurement Area Description 32 bytes Transaction Hash All bits are zero: Not a transaction hash reference 4 bytes Output Index All bits are ones: 0xFFFFFFFF 1–9 bytes (VarInt) Coinbase Information Measurement Size of the coinbase knowledge, from 2 to 100 bytes Variable Coinbase Information Arbitrary knowledge used for further nonce and mining tags. In v2 blocks; should start with block peak 4 bytes Sequence Quantity Set to 0xFFFFFFFF
See additionally BIP-34